Polymeric based and surface treated metallic hybrid materials and fabrication methods thereof

a hybrid material and polymer technology, applied in the direction of impression caps, dental prostheses, prostheses, etc., can solve the problems of stress shielding, stress shielding effect, bone loss around the implant, etc., and achieve poor biocompatibility, poor bulk mechanical properties, and rapid degradation

Inactive Publication Date: 2011-07-07
VERSITECH LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

The present invention is about creating new materials that combine biodegradable polymers and surface-treated biodegradable metallic materials. These materials have improved properties compared to traditional biodegradable materials, such as magnesium, which can have mismatched mechanical properties, poor biocompatibility, and rapid degradation. The invention allows for the manipulation of degradation by controlling the chemistry of polymeric materials and the surface treatment of metallic materials, as well as their ratio. The hybrid materials have several applications, including orthopedic implantation. The fabrication methods involve surface treatment of the metallic material, dissolving the polymer in a solution, sonication, and heat treatment. The resulting hybrid material has improved mechanical properties and controlled degradation.

Problems solved by technology

One important issue with implants is that due to biomechanical and physiologic requirements, an implant material should have a certain mechanical strength or elasticity to be incorporated into the target tissue and anatomic region.
On the other hand, they are often stiffer than natural bone, resulting in stress shielding.
Existing permanent metallic implants for fracture fixation and total hip replacement can often cause stress shielding effects due to the mismatch of the mechanical properties between these metallic implants and natural bone.
That is, due to a mismatch of the mechanical properties between these metallic implants and natural bone, the major obstacle in using these non-degradable permanent metal implants is that they may cause stress shielding effects, thereby leading to bone loss around the implant.
However, existing polymeric implants often do not have appropriate mechanical strength to withstand load-bearing conditions.
However, in addition to a mismatch in mechanical properties and poor biocompatibility, magnesium alloys exhibit problems with a rapid degradation rate and hydrogen gas accumulation upon implantation.
Rapid corrosion results in the release of a large amount of magnesium ions together with a large volume of hydrogen gas generated.
Although alloying can improve the corrosion resistance of magnesium alloy, this technique may introduce biological toxicity due to the use of rare earth metals, such as cerium and yttrium.
Additionally, the compatibility with living cells remains a problem.
However, there is still a discrepancy between magnesium alloy and natural bone in terms of bulk mechanical properties.
Each of the existing materials used for orthopedic implants exhibits potentially harmful problems.

Method used

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  • Polymeric based and surface treated metallic hybrid materials and fabrication methods thereof
  • Polymeric based and surface treated metallic hybrid materials and fabrication methods thereof
  • Polymeric based and surface treated metallic hybrid materials and fabrication methods thereof

Examples

Experimental program
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Effect test

example 1

Plasma Immersion Ion Implantation (PIII)

[0039]One of the surface modification methods can be PIII, and the implantation sources that can be used include nitrogen (N2), oxygen (O2), carbon (C), ammonia (NH3), aluminum (Al), zirconium (Zr), iron (Fe), silicon (Si), strontium (Sr), calcium (Ca), and water. Table 1 shows implantation conditions for the implantation sources of nitrogen, water, and strontium. All values listed will work with slight variations, such that each value should be interpreted as having the word “about” in front of it.

TABLE 1Implantation conditions for PIII for selected implantation sourcesSourcesParametersNitrogen (N2)Water (H2O)Strontium (Sr)Base Pressure7.0 × 10−6 Torr7.0 × 10−6 Torr7.0 × 10−6 TorrWorking Voltage40 kV40 kV15 kVPulse Width30 μs30 μs30 μsImplantation Time4 hrs4 hrs3 hrsFrequency200 Hz200 Hz200 HzWorking Pressure5.0 × 10−4 Torr6.0 × 10−4 Torr6.4 × 10−4 Torr

example 2

Plasma Immersion Ion Implantation and Deposition (PIII & D)

[0040]Apart from PIII, PIII together with deposition can be used as another surface treatment technique. Similar to PIII, different sources such as nitrogen (N2), oxygen (O2), carbon (C), ammonia (NH3), aluminum (Al), zirconium (Zr), iron (Fe), silicon (Si), strontium (Sr), calcium (Ca), and / or water can be used for PIII & D. Table 2 shows the working parameters for implanting and depositing Al and O2 at the same time. All values listed will work with slight variations, such that each value could be interpreted as having the word “about” in front of it.

TABLE 2Implantation and deposition conditions for implanting and depositingAl and O2 to form Al2O3Negative High Voltage Power SupplyNH Current1.0 mANH Voltage15 kVPulse Duration300 μsFrequency10 HzPulsed Filtered Cathodic Arc SourceArc Current0.1 AArc Voltage92 VTriggering Voltage12.6 kVCoil Current2.3 APulse Duration250 μsFrequency10 HzOxygen Flow10 sccm

example 3

Magnetron Sputtering

[0041]Magnetron sputtering can be used for a surface treatment process according to an embodiment of the subject invention. The sputtering source can be, for example, aluminum oxide (Al2O3). Tables 3 shows the process conditions during the magnetron sputtering process. All values listed will work with slight variations, such that each value could be interpreted as having the word “about” in front of it.

TABLE 3Process conditions of magnetron sputteringFrequency40 kHz-60 kHzVoltage100-1000 VCurrent0.1-1 A

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Abstract

Novel hybrid materials and fabrication methods thereof are provided. The novel hybrid materials can include a biodegradable polymer and a biodegradable metallic material. The hybrid material can also include a coupling agent between the biodegradable metallic material and the biodegradable polymer. A method of fabricating a hybrid material can include performing a surface treatment process on the biodegradable metallic material, and then either performing a solvent formation method or a thermal formation method.

Description

CROSS-REFERENCE TO RELATED APPLICATION[0001]The subject application claims the benefit of U.S. Provisional Application Ser. No. 61 / 225,279, filed Jul. 14, 2009, which is incorporated herein by reference in its entirety.BACKGROUND OF THE INVENTION[0002]Implants are used very often in surgical, orthopedic, dental, and other related applications, including tissue engineering. One important issue with implants is that due to biomechanical and physiologic requirements, an implant material should have a certain mechanical strength or elasticity to be incorporated into the target tissue and anatomic region. Also, degradability or possibly even incorporating pharmacologically or therapeutically active agents is also desirable.[0003]Several different materials for implants have been used, including metal. Metallic implant materials are usually favorable in terms of toughness, ductility, and fatigue resistance. On the other hand, they are often stiffer than natural bone, resulting in stress s...

Claims

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Application Information

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Patent Type & AuthorityApplications(United States)
IPC IPC(8): A61L27/44
CPCA61L27/446A61L27/58A61L2400/18C08L67/04
InventorWONG, KAREN HOI MANYEUNG, KELVIN WAI KWOKCHEUNG, KENNETH MAN CHEELUK, KEITH DIP KEILAM, JOHN KIN ONCHU, PAUL KIM HO
OwnerVERSITECH LTD